SEGV during startup on Power 8 system

[Paul Menzel]

Trying to start Firefox 61 on Power 8 terminates with the segmentation fault below.

firefox[155767]: unhandled signal 11 at 00007402b3100060 nip 0000090b2d83e9ec lr 0000090b2d83ed1c code 2
0x000000010000e96c in arena_t::SplitRun (this=0x7ffff7700000, aRun=0x7ffff4a10000, aSize=1048576, aLarge=false, aZero=false)
    at /build/firefox-aPxmMP/firefox-61.0.1+build1/memory/build/mozjemalloc.cpp

[Paul Menzel (paulmenzel)]

Here is the backtrace when starting it with `firefox -g`.

```
#0 0x000000010000e96c in arena_t::SplitRun(arena_run_t*, unsigned long, bool, bool) (this=0x7ffff7700000, aRun=0x7ffff4a10000, aSize=1048576, aLarge=false, aZero=false) at /build/firefox-aPxmMP/firefox-61.0.1+build1/memory/build/mozjemalloc.cpp:2334
#1 0x000000010000ed1c in arena_t::AllocRun(unsigned long, bool, bool) (this=0x7ffff7700000, aSize=1048576, aLarge=false, aZero=false) at /build/firefox-aPxmMP/firefox-61.0.1+build1/memory/build/mozjemalloc.cpp:2558
#2 0x0000000100010f70 in arena_t::GetNonFullBinRun(arena_bin_t*) (this=<optimized out>, aBin=0x7ffff77008d8) at /build/firefox-aPxmMP/firefox-61.0.1+build1/memory/build/mozjemalloc.cpp:2808
#3 0x000000010001306c in arena_t::MallocSmall(unsigned long, bool) (aZero=true, aSize=<optimized out>, this=0x7ffff7700000) at /build/firefox-aPxmMP/firefox-61.0.1+build1/memory/build/mozjemalloc.cpp:2954
#4 0x000000010001306c in arena_t::Malloc(unsigned long, bool) (aZero=true, aSize=<optimized out>, this=0x7ffff7700000) at /build/firefox-aPxmMP/firefox-61.0.1+build1/memory/build/mozjemalloc.cpp:3011
#5 0x000000010001306c in BaseAllocator::calloc(unsigned long, unsigned long) (aSize=<optimized out>, aNum=<optimized out>, this=<synthetic pointer>) at /build/firefox-aPxmMP/firefox-61.0.1+build1/memory/build/mozjemalloc.cpp:4190
#6 0x000000010001306c in Allocator<MozJemallocBase>::calloc(unsigned long, unsigned long) (arg2=<optimized out>, arg1=<optimized out>) at /build/firefox-aPxmMP/firefox-61.0.1+build1/memory/build/malloc_decls.h:38
#7 0x000000010001306c in calloc(size_t, size_t) (arg1=<optimized out>, arg2=<optimized out>) at /build/firefox-aPxmMP/firefox-61.0.1+build1/memory/build/malloc_decls.h:38
#8 0x00007ffff570b8e0 in xcb_connect_to_fd () at /usr/lib/powerpc64le-linux-gnu/libxcb.so.1
#9 0x00007ffff571318c in xcb_connect_to_display_with_auth_info () at /usr/lib/powerpc64le-linux-gnu/libxcb.so.1
#10 0x00007ffff57139b0 in xcb_connect () at /usr/lib/powerpc64le-linux-gnu/libxcb.so.1
#11 0x00007ffff65929fc in _XConnectXCB () at /usr/lib/powerpc64le-linux-gnu/libX11.so.6
#12 0x00007ffff657b6e4 in XOpenDisplay () at /usr/lib/powerpc64le-linux-gnu/libX11.so.6
#13 0x00007ffff67be32c in () at /usr/lib/powerpc64le-linux-gnu/libgdk-3.so.0
#14 0x00007ffff6771f68 in gdk_display_manager_open_display () at /usr/lib/powerpc64le-linux-gnu/libgdk-3.so.0
#15 0x00007ffff676efac in gdk_display_open () at /usr/lib/powerpc64le-linux-gnu/libgdk-3.so.0
#16 0x00007ffff272cbf4 in XREMain::XRE_mainStartup(bool*) (this=0x7fffffffd978, aExitFlag=0x7fffffffd8f8) at /build/firefox-aPxmMP/firefox-61.0.1+build1/toolkit/xre/nsAppRunner.cpp:4081
#17 0x00007ffff27313ec in XREMain::XRE_mainStartup(bool*) (aExitFlag=0x7fffffffd8f8, this=0x7fffffffd978) at /build/firefox-aPxmMP/firefox-61.0.1+build1/obj-powerpc64le-linux-gnu/dist/include/nsCOMPtr.h:313
#18 0x00007ffff27313ec in XREMain::XRE_main(int, char**, mozilla::BootstrapConfig const&) (this=0x7fffffffd978, argc=1, argv=0x7ffffffff068, aConfig=...) at /build/firefox-aPxmMP/firefox-61.0.1+build1/toolkit/xre/nsAppRunner.cpp:4964
#19 0x00007ffff2731910 in XRE_main(int, char**, mozilla::BootstrapConfig cons...

[Joel Stanley (shenki)]

This also happens on Power9. I was able to reproduce it with upstream's trunk as of last week.

[Paul Menzel (paulmenzel)]

Firefox 62.0 was released, and the problem is still happening.

[Paul Menzel (paulmenzel)]

The upstream bug report was marked as a duplicate of #1507035 [1]. That has a patch attached [2]., fixing the issue.

Please apply as soon as possible.

[1]: https://bugzilla.mozilla.org/show_bug.cgi?id=1507035
[2]: https://hg.mozilla.org/integration/autoland/rev/236f09f4709d

[Paul White (paulw2u)]

Upstream bug #1507035 was closed "RESOLVED FIXED" on 2018-11-14 with
a target milestone of mozilla65.

@paulmenzel, has the release of Firefox 65 and/or 66 resolved the issue?

[Paul Menzel (paulmenzel)]

I tested this yesterday with Ubuntu 18.10, and Firefox did crash anymore. So this can be tagged as solved. I do not know the first fixed version though.

[Paul White (paulw2u)]

Thanks for confirming. Closing as fixed.